Method of treating molten-metal coating baths and bath produced thereby



Patented July 15, 1924.

EDWIN R. MILLRING, OF BELLEVILLE, NEW JERSEY, ASSIGNOR TO AMERICANMACHINE & FOUNDRY COMPANY, A CORPORATION OF NEW JERSEY.

ivrn'rnon'or TREATING- MOLTEN-METAL COATING BATES AND BATH rnonocnnTHEREBY.

No Drawing.

To all whom it may concern:

Be it known that I, .EDwIN R. MILLRING, a citizen of the United States,residing at Belleville, in the county of Essex and State v of NewJersey, have invented certain new of molten lead designed for use incoating iron or steel or other metals, with a protective covering toprevent corrosion or oxidation. The presence of phosphorus in a moltenmetal coating bath is very advantageous and desirable, in that it givesthe metal to be coated an afiinity for the metal of the bath, and itassists in other ways very materially in bringing about the close unionand adherence of the coating metal to the metal to be coated. It hasbeen proposed to incorporate phosphorus in molten lead baths, by the useof phosphor-tin as the incorporating medium, and in such cases there isintroduced into the bath with the phosphorus, a considera ,le amount oftin. For certain purposes suc tin in the bath is not undesirable, whilein other cases it is preferable that no tin be present and that themetal of the coating bath be wholly of lead. According to my invention Iincorporate phosphorus in the molten metal bath in a very eifectivemanner and without the addition of tin, by employing as theincorporating' medium an. alloy of phosphorus and lead; and theinvention consists in the improved method of treating molten baths toincorporate phosphorus therein, and also the improved coating bathresulting from said treatment. a

The phosphorus lead alloy I employ consists structurally of lead havingincorporated therein and distributed throughout the same, metallicphosphorus, also known as black phosphorus. This alloy may be made amongother ways, by confining phosphorus and lead in the proper proportionssay from 1 to 5% of phosphorus, in a sealed the incorporation ofphosphorus in a bath Application filed. February 8, 1923. Serial 151'0.617,843.

metal receptacle or bomb into which is introduced an inert gas such asnitrogen or carbon dioxide or the like, to displace the air. The bomb isthen heated to a temperature'of about 650 C. for about six hours, whichmay be conveniently efiected by introducing the bomb into an electricfurnace. The heat will cause the lead to become molten and thephosphorus to dissolve therein and be distributed throughout the moltenbath, such action being aided by the pressure created. within the bomb,in the neighborhood of perhaps ten atmospheres. The phosphorus leadalloy thus formed may, while still in molten condition, be added to themetal bath in which the phosphorus is to be incorporated; or thecontents of the bomb 7 may be allowed to cool and the molten mass tohardenin the form of an ingot, and in this form be added to the moltenbathf In the treatment of molten metal baths, for instance lead baths,in accordance with my invention to incorporate phosphorus therein, thephosphorus lead alloy if in the form of an .ingot, is immersed in thebath and kept fully immersed therein, with the result that the. lead ofthe alloy will be reduced to molten condition and will mingle with the,lead of the bath, and the phosphorus will be liberated and will beabsorbed in the bath without loss bybeing burned away. Orif the alloy isadded in molten condition, the bomb in which it is made may be keptheated and the .molten alloy drawn off from time to time for addition tothe bath as needed.

By the incorporation of phosphorus in metal baths through'the medium ofa phosphor-lea'd alloy, I am enabled to introduce the phosphorus withoutat the same time incorporating any other ingredients. This capability isof advantage in the treatment of lead baths designed for instance forapplying a protective coating to metals to prevent corrosion andoxidation, for which uses it is in certain cases desirable that themetal of the coating bath be wholly of lead. Such baths have had thephosphorus incorporated by using phosphor-tin as the incorporatingmedium, but with the result that a considerable quantity of tin is leftin the .bath. By

the employment of phosphor-lead as the in- Q corporating medium inaccordance with my invention, the phosphorus may be incorporated in thebath without introducing tin or any other ingredient.

While I have described my invention as applicable specifically to thetreatment of lead baths, it will be understood that it is alsoapplicableto the treatment of molten baths of other metals, the lead ofthe phosphorus lead alloy in any case mingling with the metal of thebath, and the liberated phosphorus vdissolving in the metal of the bath;

Having thus described my invention, what I claim is:

1. The method of treating molten metal baths to incorporate phosphorustherein, which consists in adding to the bath, an alloy of phosphorusand lead.

2.,The method of treating molten lead baths to incorporate phosphorustherein, which consists in adding to the .bath, an alloy of phosphorusand lead.

3. The method of treating molten baths to incorporate phosphorustherein, which consists in adding to the bath, lead containingphosphorus distributed throughout the same in the form of metallicphosphorus.

4. The method of treating molten lead baths to incorporate phosphorustherein, which consists in adding'to the bath, lead containingphosphorus distributed throughout the same in the form of metallicphosphorus.

5. The method of treating molten metal baths to incorporate phosphorustherein, which consists in adding to the bath, an alloy of phosphorusand lead in molten condition.

6. A coating bath for metals, consisting of molten metal having an alloyof phosphorus and lead fused therein.

7. A coating bath for metals, consisting of molten lead having an alloyof phosphorus and lead fused therein.

In testimony whereof I have affixed my signature hereto.

EDWIN R. MILLRING.

